Silencer



March 27, 1934. v, OLDBERG 1-:1- AL SILENCER Filed Aug. 18, 1935 I |111: 1 S m\\\ \W,\ mw /|ll|| |l|l mom@ f 0 No o M o M M D ha Il m 0 o N .o c DMG .o c W J MQW. Wmo MMV@ Q 1 mhlwmwwvwll|l 1| f III I III Il w ,D A. MIME nv; Q G C ,c m, O C II IIII C n. i L C r Mr... N Il ,TMQM vom @d OMOMDO. www U U U III 0 U wm N WW WW1 .WN

INVENTORS.

a@ my Patented Mar. :27, 1934 PATENT OFFICE SILENCER Virgil Oldberg and Robert L. Nulty, Detroit, `,Mich., assignors to Oldberg Manufacturing. Company, 4Detroit, Mich., a corporation of Michigan Application August 18, 1933, Serial No. 685,678

I 6 Claims.

This invention relates to silencers and more particularly to silencers used in connection with gases exhaustedfrom internal combustion engines.

In the Oldberg application, Serial No. 644,852, i'lled Nov. 29, 1932, there is disclosed a triple pass silencer having an outer shell containing three resonance units, and wherein each resonance unit includes an inner through shell andan intermediate shell, and wherein suitable diaphragms are positioned at longitudinally spaced intervals in each unit along the through shell.

Inasmuch as the construction of that application requires two shells for each unit, a triple pass silencer of that construction requires seven shells in all. That construction, while extremely effective as a silencer, has proven to be somewhat more expensive -than is considered desirable for certain classes'of purchasers, and for this reason it is now proposed to provide a, triple pass,

silencer which 1is lighter in weight and less expensive in construction than the silencer of that application, but which despite its being provided with less parts 'than the silencer of that application, is eiiicient and satisfactory for the uses to which it is put.

Detailed objects of the invention will be readily apparent to those skilled in the art upon referencei to the following detailed description of an embodiment of the same, reference being had to the appended drawing which shows this embodiment. In this drawing,

Fig. 1 is an elevational Asection view of the silencer, as if on the line 1-1 of Fig. 2;

` Fig. 2 is a transverse section as if on the line' ers 20 and 21. Between the intermediate headers,

are partitions 22, which divide the casing into resonance chambers 23. The inlet through shell 12 is open at both of its ends and passes through the headers 18-20 and the partitions 22, terminating atthe header 21` and opening through `it into the outlet end expansion chamber 24 formed between the headers 19-21. The return through shell 14 is also open at both its ends and connects the headers 2li-21, passing through all of the partitions 22, and thereby serving as a communication between the expansion chamber 24 and the inlet end expansion chamber 26, which is the space between the headers 18-20 at the inlet end. The outlet through shell 16 is also open at bothends and extends from the vintermediate header 20 and the inlet end expansion chamber 26 through all of the partitions 22 and the headers 2119, terminating beyond the header 19 to provide an outlet. Both of theintermediate headers are provided with' a tri-foil opening in which seat the three through shells.

- The ow of gases, as indicated by the arrows. is as follows: Gas entersthe silencer through the open end 30 of the inlet through shell 12 and discharges into the outlet end expansion chamber 24, from where the gas returns through return through shell 14 into inlet end expansion chamber 26, from where it outlets through outlet .through shell 12 and the open end 32 of the latter.

The through shells 12 and 16 are perforated at 33--34 in alternate ones of the resonance chambers 23 formed between the partitions 22, substantially as indicated, and it will be observed that substantially all of the area of a through shell in a chamber 23 is perforated. The return through shell 14, in every one of the chambers 23, is provided with a single row of perforations 35.' There is thus formed in each chamber 23 a communication between one and only one of the through shells 12 or 16 and the return through shell 14, which communication tends to reduce the back pressure in the silencer by providing spaced by-passes along the length of the gas course and that these by-passes are restricted enough so that they will not interfere with the resonance action provided by the chambers 23 and the communications through perforations 33-34 from one of the through shells 12 or 16 to these chambers.

The action of the silencer is as follows: The gas travels through the through shells 12, 14, and 16, land sound waves accompanying them are resonated in the chambers 23 alternately. Slmultaneously with the flow oi gases through the shells, there exists a restricted flow of gases through the by-passes formed by the perfora-4 tions 33-34 in the through shells 12-16 and the perforations 35 in the return through shell 14, which Icy-passes, as explained above function effectively to reduce the back pressure that might otherwise exist if such by-pass means were omitted.

It is observed that by providing perforations 33-34 on the through shells 12, 16, in alternate ones of the resonance chambers 23 instead of on each of these through shells in each of these chambers, that no interference with the resonance action is created, as would be the case if each of the through shells 12and 16 were perforated in each chamber 23.

It Will also be observed that the shells 12, 14, and 16 as shown are'in relative tangential engagement in order that they may relatively brace one another. However, it is clearly understood that they might well be relatively spaced radially in which case the advantages gained by relative bracing would be eliminated.

It will also be observed that various engaging parts of the silencer are welded to one another in any desired manner at certain desired points, and that non-weldedslip type, expansion joints, are provided at certain other points to permit relative movement between the through shells and the partitions and the casing, caused by relative expansion of the parts.

It `will also be observed that while the silencer is of the return bend or triple-pass type, it will nevertheless function without creating an objectionable degree of back pressure, this being due to the fact that at no time, do the coursing gases encountersuch.obstructions as will tend to baffle themand to build up back pressure, and that the reduction of back pressure is enhanced by the vkay-passes previously described. However, while the-silencer functions without lbuilding up an objectionable degree of back pressure, it serves to break up the pressure impulses therein in at least two places, namely, in the expansion chambers 24 and 26.

' Still further, the reverse turns provided by this construction operate effectively to prevent the emergence of flames from the outlet 32 and eliminates the necessity of providing flame prevention means for the silencer.

Still further, it can be observed that the effective length of the'silencer is approximately the aggregated length of the through shells, and is there- `fore much greater than the actual length of the silencer. Accordingly the silencer here shown may noises. Such rigidity is produced by thel headers 18-21, the partitions 22, and the tangential engagement of the through shells. i

Further, due to the fact that pressure impulses. react at and against the ends of the silencer, rather than against central parts of the casing itself, -shell noises are still further reduced.

It will also be observed that the construction of the silencer is such that it may be readily assembled, and in a manner that would be obvious to anyone skilled in the art.

It will also be observed that while the perforations 35that communicate the return through shell 14 with the chambers 23 are shown as a single row of small perforations, they might well be otherwise formed, it being merely necessary that restricted openings or throats be provided for this purpose. At the present time it is considered desirable and possibly necessary that the effective `l area of the openings 35 be less than the effective area of the openings 33-34 inthe shells 12-16 in t the respective chambers.

Now having described a preferred embodiment of the' invention, chosen by way of example, reference will be had to the following claims for an illustration of the scope of the invention.

What we claim is:

l. In a multiple pass silencer, an imperforate E outer casing, inlet and outlet end headers therefor, inlet and outlet intermediate headers therefor combining with the adjacent end headers to form inlet and outlet end expansion chambers, transverse partitions between the intermediate E headers providing in the silencer, and between the expansion chambers, a series of longitudinally arranged resonance chambers, each of which includes an entire cross-sectional slice of the interior of the casing, an inlet through shell extending i from beyond the inlet end header to and opening into the outlet end expansion chamber, and passing through the inlet end expansion chamber and through the partitions, a return through shell passing through the partitions and connecting l the two end expansion chambers, an outlet through shell opening to and extending from the inlet end4 expansion chamber beyond the outlet end header and passing through the partitions and the outlet end expansion chamber, the inlet 1| and outlet through shells being constructed to communicate alternately with the resonance chambers so that each resonance chamber is in communication with the interior of one and only one of these through shells.

2. In a vmultiple pass silencer, an imperforate outer casing, inlet and outlet end headers therefor, inlet and outlet intermediate headers therefor combining with the adjacent end headers to l form inlet and outlet end expansion chambers, 1

.transverse partitions between the intermediate headers providing in the silencer, and between the expansion chambers, a series of longitudinally arranged resonance chambers, each of which includes an entire cross-sectional slice of the interior of the casing, an inlet through shell extending from beyond the inlet end header to and opening into the outlet end expansion chamber, and passing through the inlet end expansion chamber and through the partitions, a return l through shell passing through the partitions and connecting the two end expansion chambers, an outlet through shell opening to and extending from the inlet end expansion chamber beyond the outlet end header and. passing through the partil tions and the outlet end expansion chamber, the inlet and outlet through shells being constructed to communicate alternately with the resonance chambers so that each resonance chamber is in communication with the interior of one and only l one of these through shells, the return through shell being' constructed to communicate its interior with certain of the resonance chambers.

3. In a multiple pass silencer, an` imperforate outer casing, inlet and outlet end headers therel for, inlet and outlet intermediate headers therefor combining with the adjacent end headers to form inlet and outlet end expansion chambers, transverse partitions between the intermediate headers providing in the silencer, and between 1 the expansion chambers, a series of longitudinally arranged resonance chambers, each of which includes an entire cross-sectional slice of.' the interior of the casing, an inlet through shell extending from beyond the inlet end header to` and l opening into the outlet end expansion chamber, and passing through the inlet end expansion chamber and through the partitions, a return through shell passing through the partitions and connecting the two end expansion chambers, an 1 y 1,952,139 outlet through shell opening to and extending from the inlet end expansion chamber beyond the outlet end header and passing through the partitions and the outlet end expansion chamber, the inlet and outlet through shells being constructed to communicate alternately with the resonance chambers so that each resonance chamber is in communication with the interior of one and only one of lthese through shells, the return through shell being constructed to communicate its interior with each of the resonance chambers.

4. In a multiple pass silencer, an imperforate outer casing, inlet and outlet end headers therefor, inlet and outlet intermediate headers therefor combining 4with the adjacent end headers to form inlet and outlet end expansion chambers, transverse partitions between the intermediate headers providing in the silencer, and between the expansion chambers, a series of longitudinally arranged resonance chambers, each of which includes an entire cross-sectional slice of the interior'of the casing, an inlet through shell extending from beyond the inlet end header to and opening into the outlet end expansion chamber, and passing through the inlet end expansion.

chamber and through the partitions, a return through shell passing through the partitions and connecting the two end expansion chambers, an outlet through shell opening to and extending from the inlet end expansion chamber beyond the outlet end header and passing through the partitions and the outlet end expansion chamber,V

the inlet through shell being constructed to communicate its interior with alternate ones of the resonance chambers and the outlet through shell being constructed to communicate its interior with the ones of the resonance chambers not in communication with the interior of the inlet through shell.

5. In a multiple pass silencer, an imperforate outer casing, inlet and outlet end headers therefor, inlet and outlet intermediate headers therefor combining with the adjacent end headers to form inlet and outlet end expansion chambers, transverse partitions between the intermediate headers providing in the silencer, and between the expansion chambers, a. series of longitudinally arranged resonance chambers, each of which includes an entire cross-sectional slice of the interior of the casing, an inlet through shell extending from beyond the inlet end header to and opening into the outlet end expansion chamber, and passing through the inlet end expansion chamber and through the partitions, a return through shell passing through the partitions and -connecting the two end expansion chambers, an

outlet through shell opening to and extending from the inlet end expansion chamber beyond the outlet end header and passing through the partitions and the outlet end expansion chamber, the inlet through shell being constructed to communicate its interior with alternate ones of the resonance chambers and the outlet through shell being constructed to communicate its interior with the ones of the resonance chambers not in communication with the interior of the inlet through shell, the return through shell being constructed to communicate its interior with certain of the resonance chambers.

v6. In a multiple pass silencer, an imperforate outer casing, inlet and outlet end headers therefor, inlet and outlet intermediate headers therefor combining with the adjacent end headers to form inlet and outlet end expansion chambers, transverse partitions between the intermediate headers providing in the silencer, and between the` expansion chambers, a series of longitudinally arranged resonance chambers, each of which includes an entire cross-sectional slice of the interior of the casing, anr inlet through shell extending from beyond the inlet end header to and opening into the outlet end'expansion chamber, and passing through the inlet end expansion chamber and through the partitions, a return through shell passing through the partitions and connecting the two end expansion chambers, an outlet through shell opening to and extending from the inlet end expansion chamber beyond the outlet end header and passing through the partitions and the outlet end expansion chamber, the

inlet through shell being constructed to com- 

